Most inorganic glasses at room temperature typically demonstrate values of electrical resistivity well in excess of 10.sup.8 ohm cm. However, it has long been recognized that a transparent membrane with high ionic conductivity would have considerable value. Thus, glasses with low electrical resistivities can have utility in electrochemical devices which demand high ionic conductivity.
The high ionic conductivity of copper and silver ions is well-known and glasses containing those ions have been formulated. Nevertheless, this prior research has not fully exploited the full capability of such glasses. For example, such glasses may exhibit an electrochromic phenomenon due to the electrochemical reduction of the copper and/or silver ions to the respective metal.